ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 345 
The cerebral organs are evaginated from the germinal plate of the 
hinder germinal discs at a time when these still form invaginations of 
the Pilidium-ectoderm open to the exterior. They are laid clown in the 
form of hollow cones, and the cavity passes into the canal of the cerebral 
organs; both spaces communicate with the amniotic cavity during the 
embryonic life of the Nemertine. The cone bends backwards at its 
hinder end, and the bent part fuses with the straight. In this way the 
canal becomes curved, and the cerebral organ spherical in form. This 
organ never becomes completely separated from the hinder germinal 
plate. 
The oesophagus of the Pilidium passes into the fore-gut of the 
Nemertine, while the mid-gut is formed from the endodermal sac. 
Polypostia similis.* * * § — Dr. D. Bergendal describes, under this name, 
a new Polyclad, which resembles the Leptoplanidas, but is remarkable 
for the number of its male copulatory organs. Of these there are about 
twenty, and they completely surround the large female genital orifice. 
Of the male organs one is larger than the rest, and is placed more hori- 
zontally ; each of them receives from large seminal canals a short vas 
deferens. At the hinder part of the body there are about fifty organs 
similar to the male copulatory apparatus, but they have no vasa 
deferentia. Mature females have not yet been detected. 
This genus must be placed with Cryptocelides in a special family, 
which the author proposes to call the Polypostia[i]dae. Polypostia is 
very probably an extremely primitive acotylar Polyclad, which gave rise 
to the Leptoplanidse. 
The discovery of this form is of great importance, as it affords 
support to the hypothesis of Lang that the male copulatory organs of 
Polyclads are derived from other organs by transformation of function. 
Distomum Westermanni in the United States. j — Dr. H. B. Ward 
has found in the lungs of a cat a parasite which careful examination 
shows to be the Asiatic D. Westermanni. It is possible that it was 
introduced into the United States by the Chinese, but this much is 
certain, that the ova have found a host in which they can live ; it is only 
to be hoped that it may prove to be a solitary case. 
Canal of Laurer.J — Mr. Seitaro Goto has made a comparative study 
of this enigmatic organ of Distomes, and has come to the conclusion that 
it, the blind sheath of Amphilina , and the genito-intestinal canal of ecto- 
parasitic Trematodes are homologous structures ; and that the vagina of 
the last corresponds to the uterus of Amphilina. As the latter is clearly 
homologous with the organ of the same name in Bothriocephalus and the 
Tasniidse, it follows that the many-jointed Cestodes have no canal of 
Laurer at all. 
Adult Cestodes of Cattle, Sheep, and Allied Animals.§ — Dr. C. W. 
Stiles and Mr. A. Hassall have made a careful revision of the tapeworms 
* Rev. Biol, du Nord de la France, v. (1893) 3 pp. (separate copy). See also 
Fysiograf. Sallskapets Hdgr., 1892-3, Bd. 4. 
f Centralbl. f. Bakteriol. u. Parasitenk., xv. (1894) pp. 362-4. 
t Op. cit., xiv. (1893) pp. 797-801 (4 figs.). 
§ U.S. Dep. of Agriculture, Bureau of Animal Industry, Bulletin No. 4, 
Washington, 1893, 134 pp., 16 pis. 
